IC6 Pain Management & Palliative Care Flashcards
how to give PRN dosing for opioids
each PRN dose can be 10 to 20% of patient’s TDD
afterwards, consider the duration of action and give the frequency accordingly (FOR SHORT ACTING OPIOIDS).
most opioids have a duration of action of around 3-5hours = can give q4h PRN dosing.
note that if the PRN dose given before is insufficient (eg not 10%), can increase the dose accordingly.
how to increase the dose of your around the clock opioid dose
can give 50 to 100% of total PRN dose to the round the clock dose.
which opioids should caution in patients with renal impairment? and reasons
codeine
morphine
hydromorphone
hydrocodone
oxymorphone
risk of accumulation of renally cleared metabolites CAUSING neurologic effects
what is the half life of methadone and what are the other long acting opioid products
up to 15-120hours
methadone
ER versions of morphine, oxymorphone, and fentanyl
- fentanyl half life and onset is short but this is decreased with
how is codeine metabolised and function
codeine is metabolised into the active metabolite morphine via cyp2d6
how to do dose conversion for opioids?
add PRN used to scheduled = TDD
convert dose to the other opioid
adjust frequency
PRN dose
10-20% of TDD as PRN, frequency based on duration of action
- note if patient was well controlled with PRN dosing, can consider converting from the PRN dose directly.
morphine to fentanyl dosing conversion (NCCN) AND dosing considerations
2mg PO morphine = 1mcg/hr fentanyl patch
can maintain the PRN dosing of morphine as needed…
no right dose, FTU 2 weeks and reiterate accordingly, counsel patient on SE to watch for
initiation considerations when giving fentanyl patch
patient should ideally be opioid tolerant (60mg of morphine per day)
consider if paitent has fever
- may increase absorption
dosing duration and onset for fentanyl
q72 hours
onset is slow as takes time to absorb to skin –> sc fat –> bloodstream (counsel)
counselling points for fentanyl patch
1) applied to non hairy area on upper body (chest, back, upper arm). remove hair with scissors if required.
2) wash with clean water and dry area before application.
3) avoid exposure to direct external heat (heating pads, electric blankets, intensive sunbathing, prolonged hot baths, saunas)
4) outer waterproof dressing to prevent the patch from getting wet during shower.
5) do not cut the patch/ apply damaged patch as it may alter absorption
side effects counselling for fentanyl patch
1) may cause drowsiness/dizziness = do not operate heavy machinery
2) constipation, n/v
3) addiction risk; if experience difficulty stopping the medication seek hip
4) application site rash or itch
5) depress breathing = IMMEDIATE medical attention
6) decrease BP = fainting, blurring of vision, light-headedness, dizziness = IMMEDIATE medical attention
7) AVOID ALCOHOL
morphine to methadone dosing conversion
if <60mg, = 2-7.5mg of methadone per day
60-199 = 10:1 ratio (if age <65yo)
>200 = 20:1 (and/or if age >65yo)
no more than 45mg per day
how to dose titrate methadone
no more than 5-7 days or longer
by 5mg increments
caution for methadone dose titration
time to steady state is 5-7 days,
hence if patient experiences marked improvement in pain after 2-3 days OR significant sedation = dose may be too high and risk of respiratory depression by d5-7
special dosage form details for methadone
can be crushed for PO, enteral, transmucosal administration
can be given liquid formulation
can be SL dosing
considerations before initiation/dose titration of methadone
consider ECG prior to initiation and if doses exceed 30-40 per day
or if patient has risk of ECG prolongation
special properties of ketamine (and moa + how to use)
It is a noncompetitive NMDA receptor antagonist
can be used to reverse opioid hyperalgesia
may reverse opioid tolerance
give together with opioid but reduce dose by 50% = reduce the amount of opioid you need (in tolerance)
- (hyperalgesia) a paradoxical phenomenon where long-term opioid use leads to increased sensitivity to painful stimuli = heightened pain/phantom pain.
opioid tolerance vs dependence vs addiction?
tolerance
= reduced response; need more dose
dependence
= body adjusts normal functioning around opioid use
= withdrawal when stopped
addiction
= attempts to cut down/control is unsuccessful
= use results in social dysfunction / failure to fulfil obligations at work, school, home, etc
ddi with opioids
any sedating drugs
- benzodiazepines
- antipsychotics and antidepressants
- first gen antihistamines
- gabapentin/pregabalin
ALCOHOL!!!
drug disease interactions with opioids
history of
- seizure
- liver/kidney impairment
- HYPOtension
- irregular heart rhythm
- respiratory conditions (COPD, asthma)
- chronic constipation
- urinary retention
- alcoholism or history of illicit drug use
what are the withdrawal sx of opioids q
sweating,
gastrointestinal cramps,
diarrhoea and
muscle ache.
If these occur, consult your doctor.
what are some adjuvant agents for pain
GABApentin, preGABAlin
SNRI (duloxetine)
tramadol
lidocaine
management of end of life:
dyspnoea sx
non phx recommended
- oxygen therapy
morphine PRN may be used to depress respiratory rate
can consider furosemide for fluid overload AND benzodiazepines (if life expectancy is weeks to days)
management of end of life:
secretion sx
glycopyrrolate
or
anticholinergics (atropine, scopolamine)
management of end of life:
agitation/delirum
consider precipitating causes eg drugs, dementia, etc
antipsychotics last resort (haloperidol, olanzapine at lowest effective dose, shortest duration)
other common ailments for end of life
anorexia / cachexia (loss of more than 10% of body weight)
- delayed motility /early satiety (metoclopramide)
persistent nausea
chronic diarrhoea/constipation
insomnia/over-sedation
- insomnia (melatonin, zolpidem, sedating antidepressants/psych)
- daytime sedation (caffeine)
wound pressure/ulcer sores
benefits of early palliative care
improved QOL, mood, depression scores
lower % needed aggressive end of life care
survival advantage vs normal care
how to manage constipation with opioid use
emphasise on frequent bowel movement (e.g. goal of once every 2 days?)
exercise
adequate fluid intake
adequate fibre intake
stimulant laxatives and osmotic laxatives work,
= bulk forming laxatives may worsen constipation (eg psyllium)
= docusate sodium may not be effective (emolient/stool softener)
can add another agent if consitpaiton persists
